The present invention relates to an apparatus for drying ink designs applied to curved surfaces, especially ink logos imprinted on the front surface of a cap.
It is conventional to apply a logo to the front surface of a cap, such as the application of a team logo to an athletic sporting cap for example. Such logos are typically applied by a silk screen printing process. In order to thereafter cure the ink, it is necessary to heat the ink to its particular curing temperature.
One known apparatus for performing the heating step is depicted in the accompanying FIGS. 7 and 8. That apparatus comprises an infrared heater 10 having a vertically upright heating surface 12. A conveyor belt 14 has an upper flight 16 on which caps C are placed after logos have been ink-imprinted on their front surfaces FS. The belt is driven by a motor 18 such that the upper flight 16 continuously travels in a direction D, causing the caps C to slowly pass laterally across the heating surface 12. The speed of the belt 14 is regulated with the intent of causing the ink to be fully cured by the time that the respective caps have passed out of the heating zone located immediately in front of the heating surface 12.
Such an apparatus has exhibited a number of shortcomings, however. For example, the heating surface 12 lies in a vertical plane, whereas the front surface FS (and thus also the applied logo) of a typical athletic cap is curved as viewed from above (see FIG. 7). Accordingly, the horizontally spaced end regions of the logo will be spaced farther from the heating surface than the central horizontal region.
Furthermore, the front surface FS of a typical athletic cap is inclined at a slight angle A relative to a vertical plane V as viewed from the side (see FIG. 8). Consequently, the upper regions of the logo will be spaced farther from the heating surface than the lower regions of the logo.
The non-uniform spacing of the various regions of the logo relative to the heating surface 12 means that the curing of the various regions of the logo will occur at different rates. The implications of that fact become apparent when it is realized that each ink cures at a particular temperature, and that adverse effects occur if the heating is terminated either before or after the ink reaches its respective curing temperature. For example, ink which fails to reach the curing temperature will later tend to flake-off prematurely. On the other hand, ink which exceeds the curing temperature tends to reliquify and run, thereby blurring the appearance of the logo. Also, an overheated ink may tend to become undesirably darker in color.
It will, therefore, be appreciated that if the caps remain in front of the heater long enough for the horizontal end regions and upper regions thereof to reach the curing temperature, then the intermediate regions (which are located closer to the heating surface) may tend to become excessively heated. Conversely, if only the intermediate regions of the logo reach, but do not exceed, the curing temperature, then the horizontal end regions and upper regions of the logo may not be properly cured.
Moreover, the apparatus depicted in FIGS. 6 and 7 requires a belt and drive motor and thus is rather heavy and not easily portable. In that regard, it would be desirable to provide a readily portable device which could be taken to various sites, such as fairs and sporting events at which made-to-order logos could be applied to the caps at the site (in conjunction with a suitable printing device).